Airplane propeller



D. W. MAIN AIRPIIANE PROPELLER Feb. 17, 1948.

Filed 00 s, 1942 NW T A N M W m V A D @nMaW Fig. 4

ATTaRme Patented Feb. 17, 1948 UNITED STAT-ES PATENT OFFICE i 2,486,113AIRPLANE PROPELLER David w. M in; Denver, Colo. I

Application October 5, 1942, Serial No.- 460,759

8 Claims. 1

- This invention relates to improvements in airtion Serial No. 457,623,filed September 7,1942, a

now Patent No. 2,397,189, issued March 26, 1946. One of the objects ofthis invention is to pro vide a simple andreliable mechanism forimproving the maneuverability of airplanes and to produce greaterlifting power at the take-off whereby .the airplane can be launchedfrom-a shorter field and whereby it may take-ofi with a greater load ona given take-off run.

-Another object is to produce an airplane of greater than ordinarystability. v.

A further object is to produce an airplane of great climbing power bymeans of which agiven altitude can be reached in a very short time.

A still further object is to produce a mechanism that will serve toproduce both a lifting and attractive force and which shall also beprovided with means. for proportioning and varying the lifting andtractive f'orcesduring' flight.

The above and other objects that may become apparent as the descriptionproceeds and others to which attention may be directed are obtained bymeans of a construction and an arrangement of parts that will now be'described in detail and for this purpose reference willwbe had to theaccompanying drawing in which the invention has been illustrated, and inwhich: s j a Figure 1 is a perspective view showing my invention appliedto an airplane;

Figure 2 is a front elevation showing them vention separated from theairplane; 1; 1

Figure 3 is a section-taken .on lines 3-3, Fig.

- Figure 4-is a section taken on lines 4 4, Fig- Figure 5 is a frontelevation of one of the vanes. ofa rotating member; Figure 6 is atopplan view-shown in a mii fe or, less diagra'mmatic manner of the mecanism shown in Figure 2 j J Figure 7 is a view sonl whatsimilar to thatshownin Figure 2, but showing a slightl'yfmodifled form ofconstruction.- In the drawing reference numeral l 0 designates thefuselage of an airplane which, 'in'this particular case is provided withcoaxial propellers [land with Wings 12. Positioned funderneath. thewings are auxiliary propellers, and liftingdevices comprising twoelongated rotors which have .beendesignated by letters A and l}.-.Theconstruction of the auxiliary devices will now be 20 which a pin22extends.

describedand' for this purpose reference will be had more particularlyto Figures 2, 3, 4 and 5.

'A shaft i3 is journaled in suitable bearings in thefuselage I 0 andextends through another bearing in a downwardly extending bracket l4.Surrounding the shaft is a hollow cylindrical member l5 from oppositeends of which spokes l6 radiate. The outer ends of the spokes areforwardly curved as shown at I! in Figures 3 l0 and 4 and the extremeends are connected by means of a bar l8. Positioned between the bar i8and the outer circumference of the cylinder l5 are blades l9. .Theseblades are of streamline cross section as shown quite clearly inFiguresll 3 and 4. The blades are pivotally connected with the spokesl6. One end pivot extends through the spoke and terminates in a crankarm. 20. The outer ends ofthe crank arms are pivotally connected to aconnecting rod 2| from The axes of the cranks are inclined atapproximately 45 degrees to the planes of the blades so that when thelatter moves through 90 degrees, in the manner to be; hereinafterexplained, the crank arms will never 25 make an angle of less than 45degrees with the spokes. Secured to or formed integral with the bearingthrough which shaft l3 extendsis a circular disk 23 that is provided onthe surface adjacent the rotating element with a cam groove ,9 which hasbeen shown by broken lines in'Figurethatwhen the pin or pins 22 are inthe circular are 24 the-blades will project substantially pen"pendicular to the axis of the spokes in such a way that when the memberrotates the blades will cut the air in the manner of a knife blade.

#9 When the pin 22 reaches the inclined portion 26 of the groove,it willmove outwardly until itenters the arcuate groove 25 and during; thismovement the blades lll will close until they assumethe position shownin the lower righ hand -portion of-Figure 4. When the pinigj reaches thelowermostinclined section 26, the

blades will again be moved into open position. The feathering of theblades that is efiected by the blades, they must be straight between thepivots and in order to effect this they are constructed in a mannershown in Figure 5 in which 7 a member 21 connects the inner ends of thespokes and has a curved edge that fits the outside of the cylinder [5.

Although a single rotor will exert a consider 18 has a tendency toproduce severe strains in stopping and starting and although not shownon the drawing, some resilient cushioning means is contemplated for thepurpose of cushioning the blades on closing and producing a resilientforce tending to move them to open position.

In the present embodiment the wings l2 have been shown of ordinaryconstruction, but under certain circumstances the wings may be more orless skeletonized so as to have the airplane depend more directly forits supporting force on ,the operation of the rotating members.

By means of the cam disk 23, the particular periods in the rotation whenthe blades open and able effect, better results will be obtained if an-;

other rotor B is connected therewith in the manner shown in the drawing.The rotor B is-up-- wardly and rearwardly inclined and its shaft 28 hasits inner'end pivoted in a' bearing'29 that has been shown asbeing'integrally connected with bracket I4. A cam' plate 231: is securedto the bearing'29 and operates in the same manner as explainedinconnection with Figure 4. The upward and outward inclination of theblades produces a stream of air that flows upwardly and rearwardly,thereby stabilizing the airplane at the same time that it effects atractive and lifting force.

It may be desirable to adjust the cam plates 23? and 23a rotariallyduring flight so-as to vary the portion betweenthe lifting and thetractive effort, and in Figures 2 and 'I'means have been indicated forthis purpose, Cam plates 23 and 23:; are formed on their outer edgeswith sprocket teeth and a shaft 3! is journaled in bearings in thefuselage and also in the bracket M. Secured to the shaft are twosprocket wheels 32 and 33 that are connected by means of sprocket chainswith the cam disks. A' crank 35 has been indicated as means for rotatingthe shaft 3 I When thus equipped the operator can vary the eifect of theauxiliary means to better suit various operating conditions. Theadjusting mechanism shown in Figures 2 and 7 is merely illustrative ofmeans and such modifications may be made as become necessary toaccomplish the result desired. For example, instead of the crank 35connected directly with shaft 3!, a worm gear drive may be substitutedas this is nonreversible and self-locking.

Greater adaptability can be had if sections A and B are rotatedindependently so that their speed of rotation may be adjusted to obtainthe best results and this can be effected by making the shaft l3 tubularand inserting therethrough the shaft 28 to which the universal 30 isconnected.

Referring again to Figure "7, attention is called to the fact that inthis modification the rotor B hasbeen shown as rigidlyv connected to aninclin'ed portion of shaft 28a, as in the construction shown inFigure2,ywhich rotates about an axis substantially coincident with thatof shaft l3. This is effected by providing the shaft 28a with an outercrank arm 36 that terminates in a simulates the action of a birds' wingduring flight and greatly increases the effectiveness of this mechanism.

The rapid opening and closing of the blades close can be varied and itis therefore possible to so adjust the parts that section A effectsprimaril-ya tractiveeifort, while section B is di-,

rected more particularly to producing a lifting for'ce-o'r thisarrangement may be reversed, if desired. Instead of a single means forsimultaneously, adjusting both cam'i disks a separate means may beprovided for each so that thetwo rotors may be adjusted. differently inaccordance with the exigencies of the situation. By means oftheadjustment of the blades, it is possible to produce such largeliftingforces that the. plane may travel very slowly over an object, therebymaking it possible to more'accurately discharge bombs or otherprojectiles.

In the embodiment illustrated, the actual rotors are provided under eachwing only, but-.it is possible and some times preferable to also providethe stabilizing wings at the .rear of the fuselage with similar devicesin which caseethe'airplane will have addedlifting power and increasedstability. 7

Although the propelling devices have been shown as applied to anairplane having the usual form of tractor propeller and have beenreferred to as auxiliary propellers, itis to be understood that bysuitably modifying the plane construction, .the usual propeller may beomitted.

On the drawing and in the above description. sections A and B have beenshown and described as rotating at the samespeed which is quite usualand whichmay be: accomplishedvby connecting the two shafts l3 and28' bythe universa1s30.

In theabove description and on the drawings two sections A and B havebeen described and shown. In some instances 'itmay be desirable toemploy a single section, like A, and.so construct the same that thetractive effort and the lifting effort can be independently modified bysuitable means, as, for example, means for changing the effect of theradial depth of the vanes or'their pitch or their angle ofattack.

Referring to Figure 4, reference numeral 26,- it will be noted thatunder the arrangement shown the blades are reversible at this point inorder to continuously-present their-leading edge in the direction ofrotationfor more effective performance: It'has been found that reversalor.

flipping of the blades in this area adds a function of additionalpropulsion. As actually constructed, the mounting of pivot point of theblades closer to the leading edgethan to the following edge andtherefore the blades tend to turn in the desired direction dueto'natural forces and espe cially where the channel is widened betweenthe areas 26 and 24 left handside. The bladesmay then be allowed to hunttheir own best position with least amount of drag through a sectionwhere normally only negative results are obtained.

Having described the invention, what is claimed as new is:

1. In an airplane having a fuselage, and at least one pair of wings,propelling and lifting means associated with the airplane comprising,elongated propeller elements extending laterally from opposite sides ofthe fuselage, each propeller element comprising two sections, thesections nearest the fuselage being mounted for rotation about axessubstantially perpendicular to the axis of the fuselage, means forrotating the elements in such a direction that their front surfaces movedownwardly, the outer sections being mounted for rotation about upwardlyand rearwardly extending axes, means for transmitting motion to theinner section, means for transmitting motion to the outer sectionscomprising a universal joint, each section having a plurality of radiallongitudinal spaced spokes, blades positioned between the spokes andmounted for rotation about their axes from open to closed position, andmeans comprising a cam mechanism associated with each section foralternately opening and closing the blades as the section rotates.

2. In an airplane having a fuselage, and at least one pair of wings,propelling and lifting means associated with the airplane comprisingelongated propeller elements extending laterally from opposite sides ofthe fuselage, each propeller element comprising two sections, thesections nearest the fuselage being mounted for rotation about axessubstantially perpendicular to the axis of the fuselage, means forrotating the elements in such a direction that their front surfaces movedownwardly, the outer sections being mounted for rotation about upwardlyand reanwardly extending axes, means for transmitting motion to theinner sections, means for transmitting motion to the outer sectionscomprising a universal joint, each section having a plurality of radiallongitudinally spaced spokes, blades positioned between the spokes andmounted for rotation about their axes from open to closed position,means comprising a cam mechanism associated with each section foralternately opening and closing the blades as the section rotates, andmeans for adjusting the positions of the cams during operation.

3. A device in accordance with claim 1 in which the blades extendhelically about the sections of the propeller elements.

4. A device in accordance with claim 2 in which the blades extendhelically about the sections of the propeller elements.

5. A device in accordance with claim 1 in which means is provided forrotatably adjusting the cams.

6. A device in accordance with claim 2 in which means is provided forrotatably adjusting the cams.

7. A device in accordance with-claim 1 in which the two propellersections are mounted for independent rotation.

8. A device in accordance with claim 2 in which the two propellersections are mounted for independent rotation.

DAVID W. MAIN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,898,638 Martin Feb. 21, 19331,796,016 Fricke Mar. 10, 1931 1,186,650 Crow June 13, 1916 1,796,860Bowers Mar. 17, 1931 1,927,538 Zaparka Sept. 19. 1933 1,010,443 MinnichDec. 5, 1911 1,004,662 Kuenzel Oct. 3, 1911 2,123,916 Rohrbach July 19,1938 FOREIGN PATENTS Number Country Date 15,890 Great Britain 190723,129 Great Britain Oct. 30, 1908

